1. Field of the Invention
This invention relates to an arc discharge prevention connector and an arc discharge prevention circuit each having a contact protection function.
2. Description of the Related Art
A conventional connector includes a female connector and a male connector which are fitted to each other for connection. The female connector has a female connector housing in which a male connection terminal is housed and fixed. The male connection terminal is disposed so that a tip is protruded into a hood of the female connector housing.
On the other hand, the male connector has a female connector housing in which a female connection terminal is housed and fixed. The female connection terminal has the front end formed in a tubular shape into which the tip of the male connection terminal can be inserted. The female connection terminal also has a connection spring piece at the front end, which piece is folded back obliquely into the internal space of the tube.
However in this connector, when the male connector is fitted into the female connector in a conductive state and the tip of the male connection terminal first makes contact with the front end of the female connection terminal, there occurs such a problem as to generate arc discharge at the contact to deteriorate or damage the contacts. When the connectors are disengaged, the tip of the male connection terminal is lastly disengaged from the front end of the female connection terminal. In this connection, there is a problem of generating arc discharge at the corresponding part to deteriorate or damage the contacts.
The present invention has been achieved with such points in mind.
It is therefore an object of the invention to provide an arc discharge prevention connector and an arc discharge prevention circuit each having a contact protection function to prevent deterioration of or damage to the tips of connection terminals connected to each other, to protect the tips of the connection terminals.
To achieve the object, according to a first aspect of the invention, there is provided an arc discharge prevention connector comprising: a first and a second connector housings to be fitted to each other; a first connection terminal for main power supply disposed in the first connector housing; a first connection terminal for signal disposed in the first connector housing; a second connection terminal for main power supply disposed in the second connector housing, the second connection terminal for main power supply being arranged to be connected to the first connection terminal for main power supply; and a second connection terminal for signal disposed in the second connector housing, the second connection terminal for signal being arranged to be connected to the first connection terminal for signal, wherein the first connection terminal for main power supply is configured to make contact with the second connection terminal for main power supply before the first connection terminal for signal makes contact with the second connection terminal for signal when the first connector housing and the second connector housing are fitted to each other; and the first connection terminal for signal is configured to break contact with the second connection terminal for signal before the first connection terminal for main power supply breaks contact with the second connection terminal for main power supply when the first connector housing and the second connector housing are disengaged from each other.
Thus in this invention, when the arc discharge prevention connector is set in such a manner that, for example, the first connection terminal for main power supply and the second connection terminal for main power supply come into a conductive state upon the connection between the first connection terminal for signal and the second connection terminal for signal, and conversely, the conductive state of the first connection terminal for main power supply and the second connection terminal for main power supply is broken upon the breaking of the connection between the first connection terminal for signal and the second connection terminal for signal, it becomes possible to prevent the generation of arc discharge between the first connection terminal for main power supply and the second connection terminal for main power supply at the time of the connection or the breaking of the connection. As a result, the first connection terminal for main power supply and the second connection terminal for main power supply can be effectively prevented from deterioration or damage due to arc discharge.
According to a second aspect of the invention, as it depends from the first aspect, the first connection terminal for main power supply and the second connection terminal for main power supply are connected to constitute a main power supply circuit, the first connection terminal for signal and the second connection terminal for signal are connected/disconnected to constitute a switching circuit for switching the main power supply circuit on/off, the first connection terminal for signal makes contact with the second connection terminal for signal after the first connection terminal for main power supply makes contact with the second connection terminal for main power supply in a non-conductive state as the first and second connecter housings are fitted to each other, whereby the switching circuit switches the main power supply circuit to a conductive state, and the first connection terminal for signal breaks contact with the second connection terminal for signal before the first connection terminal for main power supply breaks contact with the second connection terminal for main power supply as the first and second connector housings are disengaged from each other, whereby the switching circuit switches the main power supply circuit to a non-conductive state.
Thus in this invention, arc discharge does not occur between the first connection terminal for main power supply and the second connection terminal for main power supply at the time of the connection and the breaking of the connection. Thus the first connection terminal for main power supply and the second connection terminal for main power supply can be prevented from deterioration or damage. Further, power passed through the first connection terminal for signal and the second connection terminal for signal which constitute the switching circuit can be small for use in signal transmission. Thus arc discharge is unlikely to occur between the first connection terminal for signal and the second connection terminal for signal, or is very weak if generated. Therefore the first connection terminal for signal and the second connection terminal for signal can be prevented from deterioration or damage, resulting in an arc discharge prevention connector with high durability.
According to a third aspect of the invention, as it depends from the first or the second aspect, the first connection terminal for main power supply and the first connection terminal for signal are each provided with contact protrusions, so that the contact protrusions being housed and arranged in the first connector housing in such a manner that the first connection terminal for main power supply protrudes more than the first connection terminal for signal in the forward connecting direction, and the second connection terminal for main power supply and the second connection terminal for signal are put side by side in the second connector housing so that the front ends of the terminals have substantially the same position in the connecting direction.
Further, according to a fourth aspect of the invention, as it depends from the first, the second or the third aspect, the contact protrusion of the first connection terminal for main power supply has a longer length than the contact protrusion of the first connection terminal for signal.
Thus in this invention, the fitting and the disengagement of the first and second connector housings automatically switch the main power supply circuit on/off. Further it has such a simple structure as can be easily produced.
According to a fifth aspect of the invention, there is provided a main power supply circuit to which a main power supply is connected to supply a load piece with electric power, the main power supply circuit being provided with a first connection terminal for main power supply and a second connection terminal for main power supply for making/breaking thereof; and a switching circuit to open/close the main power supply circuit, the switching circuit being provided with a first connection terminal for signal and a second connection terminal for signal for making/breaking thereof, wherein the first connection terminal for main power supply is configured to make contact with the second connection terminal for main power supply before the first connection terminal for signal makes contact with the second connection terminal for signal when the first connection terminal for main power supply is fit into the second connection terminal for main power supply; and wherein the first connection terminal for signal is configured to break contact with the second connection terminal for signal before the first connection terminal for main power supply breaks contact with the second connection terminal for main power supply when the first connection terminal for main power supply is disengaged from the second connection terminal for main power supply.
Thus in this invention, such a main power supply circuit and switching circuit prevent arc discharge between the first connection terminal for main power supply and the second connection terminal for main power supply even at the time of connecting and breaking the connection of the terminals. Thus the first connection terminal for main power supply and the second connection terminal for main power supply can be prevented from being subject to deterioration or damage.